a. Field of the Invention
This invention relates to a print control system for use with a printer, and more particularly to a print control system which is capable of adapting printing by the printer to different sizes of printing paper.
b. Background Art
The most common print control system heretofore employed for a printing unit such as a laser beam printer or the like operates in such a manner that character or graphic data supplied thereto from a host unit are once developed in the form of dots on a frame memory such as a so-called full-dot memory (or bit-map memory), and then printing is carried out according to the contents of the full-dot memory. This system, however, should be adapted for a variable effective printing area which varies with the size of the printing paper.
A first possible idea to adapt for such variation of the effective printing area is such that a full-dot memory having a memory area corresponding to the maximum size of the printing paper is prepared and each data to be written into the full-dot memory is subjected to a determination, prior to writing, as to whether or not the data will be within the effective printing area so that only the data within the effective printing area may be written in the full-dot memory when it is required to print out the data on printing paper smaller than the maximum size. This method, however, is detrimental in that it needs a determination operation for each data as to whether or not it will be within the effective printing area and this determination operation requires a amount of considerable time. For this reason, the following method is considered more practical.
According to this method, a full-dot memory having a memory area corresponding to the maximum size of printing paper is preliminarily provided as in the first method mentioned above. This second method, however, differs from the first method in that data are written into the memory without considering the effective printing area. When printing is to be made on the printing paper smaller than the maximum size, unnecessary data, which will be located outside the effective printing area, are deleted or cancelled by microprogram control prior to the printing.
Various data processing techniques related to the method are disclosed, for example, in Japanese Publications of Unexamined Patent Applications (KOKAI) No. 62-210534, No. 61-256431 and No. 61-105638.
The second method, however, needs a data deletion operation to eliminate before printing the data developed on the memory but located outside the effective printing area of the printing paper. This deletion operation again requires a considerable amount of time and lowers the performance of the entire print control system.